Add set_bone_pose(bone_idx : int, t : Transform3D) to Skeleton3D

[soppermann]

Describe the project you are working on

A VR game that procedurally poses a Skeleton3D

Describe the problem or limitation you are having in your project

There is no Skeleton3D function that accepts a Transform3D to get a bone's local transform. I currently set_bone_pose_position(), set_bone_pose_rotation() and set_bone_pose_scale(), which adds unnecessary lines of code, is less efficient, and I believe it can't be used to properly set all possible transforms (i.e. shears).

Describe the feature / enhancement and how it helps to overcome the problem or limitation

Adding set_bone_pose(t : Transform3D) to Skeleton3D turns three lines of code to set local transform into one and allows for any valid Transform3D.

Describe how your proposal will work, with code, pseudo-code, mock-ups, and/or diagrams

Currently, I have:

func set_bone_local_transform(skeleton : Skeleton3D, bone_idx : int, t : Transform3D):
	skeleton.set_bone_pose_position(bone_idx, t.origin)
	skeleton.set_bone_pose_rotation(bone_idx, t.basis.get_rotation_quaternion())
	skeleton.set_bone_pose_scale(bone_idx, t.basis.get_scale())

With the change, it would be:

func set_bone_local_transform(skeleton : Skeleton3D, bone_idx : int, t : Transform3D):
        skeleton.set_bone_pose(bone_idx, t)

If this enhancement will not be used often, can it be worked around with a few lines of script?

I'm unaware of a way to access and set the local transform of each bone directly, and using set_bone_pose_position(), set_bone_pose_rotation() and set_bone_pose_scale() is a workaround in most cases, I'm unsure if it will work as expected for every possible Transform3D.

Is there a reason why this should be core and not an add-on in the asset library?

set_bone_rest() and set_bone_global_pose_override() already do this for rest poses and global poses. It makes sense to do the same for the bone pose.

[goatchurchprime]

It appears that this is now in 4.3, according to the docs https://docs.godotengine.org/en/latest/classes/class_skeleton3d.html#class-skeleton3d-method-set-bone-pose

It looks like it got in with this humongous Pull Request godotengine/godot#87888 so it can probably be closed.

Just as an aside, another reason that we needed this is that it's sometimes necessary to apply non-orthogonal bone transforms in a skeleton that will compose into orthogonal transforms. For example, if you want to undo a scaling in one axis on the previous bone, apply a rotation, and scale back in a different axis you need to multiply by a non-orthogonal basis.

[Calinou]

Closing per @goatchurchprime's comment.